Method and device for speech analysis

ABSTRACT

A device and a method for speech analysis are provided, comprising measuring fundamental notes of a speech sequence to be analysed and identifying frequency intervals between at least some of said fundamental notes. An assessment is then made as to the frequency at which at least some of these thus identified intervals occur in the speech sequence to be analysed. Among other applications are speech training and diagnosis of pathological conditions.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Application No.PCT/SE01/02482, filed Nov. 9, 2001, and claims the benefit of priorityof Swedish Patent Application No. 0004221-8, filed Nov. 17, 2000, thecontent of both of which is incorporated herein by reference.

TECHNICAL FIELD OF INVENTION

The present invention relates to a method and a device for analysing thehuman speech. The invention also relates to a method and a device forspeech training, to a method and a device for providing speech synthesesas also to a method and a device for diagnosing pathological conditions.

BACKGROUND OF THE INVENTION

When a human being is speaking, the listener receives impressions andsignals beyond what is actually uttered, i.e. the objective contents ofthe uttered words. These additional impressions and signals assist thelistener in interpreting the factual contents of the uttered words andthey also lead to a conscious or unconscious judgement of the speaker'scredibility, mood and so on.

Such additional signals could be for instance the tempo used by thespeaker, i.e. the speed with which he utters the words, and the rhythmhe uses. Also, the pitch of the voice communicates some information, andfor example deep and dark bass voices often are perceived asconfidence-inspiring and soothing.

The human speech contains one fundamental tone and a number ofhigher-pitched overtones. Thus, the fundamental note is the lowestfrequency that is perceivable at any given time, and equipment formeasuring the fundamental notes of speech and song is already known.From EP 0 821 345 and U.S. Pat. No. 6,014,617, for example,identification of the notes of human speech is already known.

In addition, it is already known that the fundamental notes of speechchange progressively, and usually such change is governed by thecontext, i.e. the contents of the speech and the environment in whichthe speech is made. Attempts have also been made to re-create suchcontext-dependent variations in speech syntheses. This phenomenon isdescribed for instance in EP 0 674 307.

In addition, the speaker's body language emits signals to the listener.

However, much information communicated via the human speech is notperceived consciously, and therefore cannot be analysed. Consequently,there is a need for means, such as methods and devices, for improvedspeech analyses and/or analyses of further aspects of the speech.

OBJECT OF THE INVENTION

Consequently, it is an object of the present invention to provide amethod and a device for speech analysis that completely or at leastpartly solve the above-mentioned problems inherent in the prior-arttechnique.

This problem is solved by means of the method and the device inaccordance with the invention.

SUMMARY OF THE INVENTION

The inventor of the present invention has shown that surprisingly alsothe continuous shift of fundamental notes that normally takes place innormal speech and the intervals used therefor are important to theperception of speech. This continuous shift of pitch is analysed inaccordance with the teachings of the invention on the basis of theintervals used in these shifts, and the occurrence of differentintervals affects the way in which the speech is perceived. Depending onthe extent of the use of different intervals, for example, the speechmay express different moods, different emotional states, differentdegrees of reliability, and so on. By means of the speech, acommunication of emotions thus takes place, which on a subconsciouslevel is perceived by the listeners depending on the intervals used, andwhich goes beyond the words actually uttered, the pitch of the voice,the tempo of the language and other obviously communicative parts of thespeech. Speakers as well as listeners normally are totally unaware,however, of this additional communicative dimension of speech.

Although the choice of intervals used in normal speech takes place on anunconscious level, it has been found that it can be affected to someextent. It is therefore possible to make use of the invention also toconsciously modify the choice of intervals in order to thus impart tothe voice and the speech certain sought-after expressions. This is partof another aspect of the present invention.

Furthermore, it has unexpectedly been found that the subconscious choiceof intervals that the human being makes when she speaks is affected bythe psychological and physiological well-being of the individual. Thus,it is possible, by means of the analysis in accordance with theinvention, to perceive deterioration of the psychological orphysiological state of the speaker and also to perceive actualpathological conditions. In many types of diseases, this may be possibleat an earlier date of the progress of a disease than is possible bymeans of many other alternative diagnostic methods. This feature is partof another aspect of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described in more detail in the following forexemplifying purposes by means of some embodiments and with reference tothe accompanying drawings, in which

FIG. 1 is a schematic flow chart of a first embodiment of a method inaccordance with the invention, and

FIG. 2 is a schematic block diagram of a first embodiment of a device inaccordance with the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1 schematically represents a flow chart of one embodiment of amethod for speech analysis in accordance with the invention. In a firststep S1 a speech sequence is recorded. This could be effected by directrecording of speech for analysis in a processing unit, the subsequentanalysis advantageously being effected in real time. However, it islikewise possible to record speech sequences in advance on a registeringmedium, such as a cassette tape, on CD discs, in computer memories, andso on.

Preferably, filtering is carried out in step S2. Such filtering couldinvolve separating-off notes that are too short, such that only notes ofsufficient duration, preferably above a predetermined time thresholdvalue, are carried forward for analysis. Alternatively or as asupplement, the filtering operation could also involve perception ofnotes of sufficiently high strength, preferably above a predeterminedamplitude threshold value. In this manner, too weak notes are screenedoff.

Alternatively or as a supplement, the filtering operation could alsoinvolve the formation of the mean value of the pitch during apredetermined time interval, and the mean value thus formed is used inthe subsequent analysis. In this manner, it becomes possible to handleglissando, i.e. gliding pitch movements over several notes, suggestionsand so on in a convenient manner.

In step S3, the notes remaining from the filtering process are analysed,whereby the fundamental notes are identified. The identification processcomprises analysis of the speech sound and identification of the lowestaudible or sounding frequency. This could be effected for example in themanner described in EP 0 821 345 and U.S. Pat. No. 6,014,617 but othermethods are likewise possible. Preferably, melismatically as well assyllabically occurring notes are identified.

However, alternatively, the identification step could instead be carriedout before the filtering step.

The thus identified fundamental notes are then further analysed in stepS4, whereby at least some intervals between close fundamental notes areidentified. Preferably, all intervals between neighbouring notes areidentified, but it is likewise possible to only identify all, or atleast the majority of the intervals that are deemed to be particularlyimportant to the current purpose of the analysis. It could likewise bejustified, at least for some applications, that the step of identifyingthe intervals does not involve establishing the frequency differencesbetween close notes only but also the direction in which the changeoccurs, i.e. ascending or descending pitch/interval.

In step 5, a suitable statistical method is used to establish ameasurement of how often intervals that are central to the analysisoccur in the speech sequence to be analysed. Such measurements couldcomprises for example one or several of:

-   -   the proportion of a certain interval among all intervals;    -   the proportion of a certain interval among a predetermined        number of intervals,    -   the proportions of occurrence of one, two or several selected        intervals.

It is likewise possible, however, and in some cases useful to determinethe occurrence of certain sequences of intervals, i.e. intervals betweenthree or several fundamental notes in succession and the locations ofthe intervals, i.e. their pitch position.

For the analysis of the thus determined intervals the followingqualities could be associated generally with different intervals:

-   -   Unison, perfect prime (R1): Thoughtful (reflective), progressive    -   Minor second (L3): Searching, orientating    -   Major second (S2): Graceful, self-exposing    -   Minor third (L3): Melancholic, passive    -   Major third (S3): Optimistic, pushy    -   Perfect fourth (R4): Friendly    -   Augmented fourth/diminished fifth/tritone (Trit): Creative,        insistent    -   Minor sixth (L6): Soft    -   Major sixth (S6): Stimulating    -   Minor seventh (L7): Painful    -   Major seventh (S7): Violent, angry    -   Octave (R8): Cheerful, encouraging.

Intervals above one octave normally may be classified and groupedseparately, or alternatively be combined with corresponding intervalsbelow one octave.

For many examinations it could be useful to separate out intervals fromthe following sub-groups [A]: unison (R1), minor second (L2), majorsecond (S2), minor third (L3), major third (S3), minor sixth (L6) andmajor sixth (S6); respectively [B]: perfect fourth (R4), augmentedfourth/diminished fifth (tritone), perfect fifth (R5), minor seventh(L7), major seventh (S7) and octave (R8).

In addition, intervals mostly occurring as ascending can becharacterised as confirming, interval mostly occurring as descending asindependent and intervals essentially occurring as ascending as often asdescending as diplomatic

Sequences that it is particularly interesting to identify are sequencescomprising notes that are part of major or minor chords, i.e.fundamental note, third and fifth. Above all, it is fundamental-positionarpeggios comprising three notes that are interesting, reversed ornon-reversed. However, the fundamental note may also occur in twopositions (i.e. interval of an octave). Also other chord sequences couldbe of interest, however, depending on the intended use of the analysis.

More particularly, it is also often interesting to compare theoccurrence of minor thirds (L3) and major thirds (S3). It is often alsointeresting to distinguish the occurrence of tritone chord movements, asalso to separate out the occurrence of and particularly repeats ofunisons (R1), especially in the case of ritardandoes. This could be asign for example of hesitation, thoughtfulness and so on. Also theposition of different intervals, i.e. the pitch level of their start orfinish could be a significant feature indicating different states.

The analysis described above may be used in various different ways. Oneapplication is for a psychological analysis of the speaker, anapplication that may be used to assess personality, the speaker's moodand emotional state and so on. The method therefore is applicable inmany cases where such psychological investigations and analyses are ofinterest, for instance in the case of employment interviews, clinicallyfor psychiatric care and the like, for lying detection purposes and soon.

It has also been found that this speech analysis may be used tointerpret the speaker's physiological well-being and in consequencethereof also for diagnosing different pathological conditions. Forexample, the occurrence of non-fundamental movements (that is tritonechord movements) appears to be reduced or disappear completely, and thatthe occurrence of minor intervals (L3) to be more frequent in manypathological conditions.

When the analysis is to be used for some definite purpose also asubsequent interpretation step S6 normally is effected. Thisinterpretation may be based on a comparison with normal values. Thesenormal values could either be general ones, or preferably be adapted tovarious categories. These categories could reflect for instance languageaffiliation, nationality and/or other environmental and contextualaspects. Alternatively, or as a supplement, the grouping into categoriescould also be based on personal properties, such as sex, age, previousexperience and so on. Various standard values and comparisons suitablymay be used as well, depending on the intended objective.

However, instead of standard values or as a supplement to a comparisonof this kind it is likewise possible to use earlier analyses made withrespect to the same speaker. In this manner, it becomes possible toperceive differences over time, changes that may he used for example toidentify pathological conditions of a mental or physiological nature.

The analysis defined above may also be used for speech trainingpurposes, in which case the assessed interval frequencies are comparedwith preferred values. These preferred values could be extracted inorder to suit different situations and emotional states. In addition,the comparison could be presented to the user, preferably in real time.It is also preferable to automatically separate out preferred measuresin order to reduce the differences between the analysed speech and thepreferred values. This may be effected by identification of for examplethe intervals for which the difference is the maximum one or theintervals that are deemed to be the most important ones, and on thebasis thereof retrieve pre-stored instructions suggesting suitablemeasures. The method of speech training may be used forlanguage-learning, for training actors, for training speaking in public,and so on.

A device for performing a method as above comprises in one embodiment ameans 1 for recording a speech sequence and a registering medium 2 forstoring the recorded sequence. The recording means could be e.g. amicrophone, and the registering medium a cassette, a data memory, a CDdisc or the like. Possibly, pre-stored speech sequences could, howeverbe used for the analysis. In addition, it is possible to carry out theanalysis in real time, in which case the registering medium could beexcluded.

The device further comprises a filtering means 3 to filter the recordedsignal. The filter could be designed to carry out some or all of thefiltering operations indicated previously. The filter could alsocomprise several filtering units.

In addition, the device comprises measuring means 4 to determine thefundamental notes of the speech signal. This device could be e.g. a DSPunit (Digital Signal Processing) or operate in the manner described inEP 0 821 345 or U.S. Pat. No. 6,014,617, which publications are includedherein as references. Other measuring means able to determinefundamental notes are also possible. Alternatively, the measuring meanscould also be arranged ahead of the filtering means.

The analysed fundamental notes are carried forward to a means 5 designedto identify the intervals between close fundamental notes in the mannerdescribed previously and the identified intervals are carried forward toa means for assessment of the frequency at which at least some of thesought-after intervals occur. Advantageously, this means could comprisea commercially available statistics programme.

The device could also comprise a comparative means 6, which is arrangedto compare the results of at least some of the interval assessments.This comparative means then preferably compares the assessed frequencyfor some or all intervals with a preferred frequency determined inadvance, as discussed earlier on. The previously determined valuespreferably are stored in a memory unit or a database 6.

Advantageously, the device also comprises an interpreting means 7arranged to analyse found differences. The interpreting means could alsobe connected to a database 8 for automatic supply of instructions formeasures, diagnoses, and so on. These instructions, results ofcomparison operations, etcetera could advantageously be presented to theuser via a presentation means 9, which could be a display, a loudspeakeror the like.

The device defined in the aforegoing preferably could be realised in aconventional PC unit equipped with a microphone and sound cards forsignal processing. The databases could either be stored in one orseveral memories in the computer or be accessible via communicationnetworks, such as the Internet.

The method and the device for analysis as described above could likewisebe used for speech-analysis control. In this case, conventional andprior-art speech synthesising methods and devices may be used, and thesemethods and devices are controlled in accordance with analyses disclosedby the invention. The synthesis could be controlled so as to conveydifferent emotional states, moods and other expressions. In addition, inthis respect the speech synthesis could be adapted to simulate differentindividuals or groups of individuals.

The invention has been described herein by means of various embodiments.It should be appreciated, however that other varieties of the inventionthan those defined herein are possible. For example, only a small numberof intervals may be identified, other intervals or groups of intervalsmay be used for the analyses, the fundamental notes may be measured inother ways, and so on. It is likewise possible to use the inventiveanalysing method and the inventive analysing device for other purposesthan for speech training and diagnosing. For example, analysis of thiskind could be used for lie detection, for preliminary judgement ofindividuals in conjunction with for example employment interviews, andso on. It is likely that a more detailed analysis of a speech sequencecould be used for identification purposes, In addition, an analysis ofthe kind taught by the invention could be used to select and to groupindividuals in different constellations and the like, allowingadjustments to be made aiming at increasing the likelihood for harmonyand co-operative conditions within the group.

These and other closely-related varieties should be regarded to beembraced by the invention as the latter is delimited by the appendedclaims.

1. (C) A method for analysing the human speech, comprising: (A)measuring sounding fundamental notes of a speech sequence to beanalysed; (B) identifying the frequency intervals between at least twoof the fundamental notes in succession; and (C) assessing the frequencyat which at least one of the frequency intervals thus identified occursin the speech sequence to be analysed wherein the measurement offundamental notes in the speech sequence to be analysed comprisesdistinguishing fundamental notes of sufficient duration above apredetermined threshold value and separating fundamental notes ofsufficient loudness, whereby only the fundamental notes thus separatedare identified.
 2. A method as claimed in claim 1, wherein themeasurement of fundamental notes in the speech sequence to be analysedcomprises separating fundamental notes of sufficient loudness above apredetermined amplitude threshold value.
 3. A method of speechsynthesizing, comprising the steps of analysing at least one speechsequence from at least one person by means of an analysing method asdefined in claim 2, and on the basis of said the analysis controllingthe production of synthetic speech on the basis of at least one aspectof said the analysis.
 4. A method as claimed in claim 3, wherein saidthe analysis comprises an appraisal of several speech sequences from thesame individual.
 5. A method as claimed in claim 3 or 4, wherein saidthe analysis comprises an appraisal of speech sequences from severaldifferent individuals.
 6. A method as claimed in claim 1, whereinmeasuring the fundamental notes in the speech sequence to be analysedcomprises establishing a pitch mean value during a predetermined timeinterval, and using the mean value thus obtained for identification offundamental notes.
 7. A method as claimed in claim 1, whereinidentifying the frequency intervals also comprises identification ofwhether the frequency interval is ascending or descending.
 8. A methodas claimed in claim 1, wherein at least minor thirds (L3) and majorthirds (S3) are identified.
 9. A method as claimed in claim 1,comprising identification of at least one frequency interval from thegroup: unison (R1), minor second (L2), major second (S2), minor third(L3), major third (S3), minor sixth (L6), and or major sixth (S6); andat least one frequency interval from the group perfect fourth (R4),augmented fourth/diminished fifth (tritone), perfect fifth (R5), minorseventh (L7), and or major seventh (S7).
 10. A method as claimed inclaim 1, wherein the identified frequency intervals are divided into atleast the following sub-groups: unison (R1), minor second (L2), majorsecond (S2), minor third (L3), major third (S3), minor sixth (L6), andor major sixth (S6); respectively: perfect fourth (R4), augmentedfourth/diminished fifth (tritone), perfect fifth (R5), minor seventh(L7), major seventh (S7), and or perfect octave (R8).
 11. A method asclaimed in claim 1, comprising identifying frequency interval sequencesbetween notes of at least one group comprising at least three of thefundamental notes in succession.
 12. A method as claimed in claim 11,wherein the identified frequency interval sequences comprise notes of amajor or minor chord.
 13. A method as claimed in claim 11, wherein theidentified frequency interval sequences comprise ascending or descendingarpeggios of major or minor chords.
 14. A device for analysing humanspeech, comprising: (A) measurement means for measuring soundingfundamental notes in a speech sequence to be analysed comprising afiltering unit for separation of fundamental notes having a durationabove a predetermined time threshold value and for separatingfundamental notes of a loudness above a predetermined amplitudethreshold value; (B) means for identifying frequency intervals betweenat least two of these fundamental notes in succession; and (C) means forestimating the frequency at which at least one of the frequencyintervals thus identified occurs in the speech sequence to the analysed.15. A device as claimed in claim 14, wherein the measurement means formeasuring fundamental notes further comprises means for establishing thepitch mean value during a predetermined time interval.
 16. A device asclaimed in claim 14, wherein the means for identification of frequencyintervals is designed to at least identify minor thirds (L3) and ormajor thirds (S3).
 17. A device as claimed in claim 14, wherein themeans for identification of frequency intervals further is designed toidentify the frequency interval sequences between notes of at least onegroup comprising at least three of the fundamental notes in succession.18. A device for synthetic speech, comprising a device for analysing atleast one speech sequence from at least one individual in accordancewith claim 14, and means for producing synthetic speech, said the meansfor producing synthetic speech being controlled on the basis of at leastsome aspect of the analysis produced by said the analysing device.
 19. Amethod for automated speech training, comprising: (A) providing anuttered speech sequence by a user; (B) measuring sounding fundamentalnotes of the speech sequence to be analysed; (C) identifying frequencyintervals between at least two of these fundamental notes in succession;(D) assessing the frequency at which at least one of the frequencyintervals thus identified occurs in the speech sequence to be analysed;and (E) comparing the estimated frequency interval frequency with apreferred frequency determined in advance for the user concerned.
 20. Amethod as claimed in claim 19, said the method further comprisingpresenting the results of the comparison between the assessed frequencyinterval frequency and the preferred frequency determined in advance forthe user concerned.
 21. A method as claimed in claim 19, said the methodfurther comprising identifying suitable measures for reduction of thedifference between the assessed frequency interval frequency and thepreferred frequency determined in advance.
 22. A method as claimed inclaim 19, wherein the method is carried out in real time.
 23. A methodas claimed in claim 19, wherein the preferred frequency determined inadvance for the user concerned comprises standard values.
 24. A methodas claimed in claim 23, wherein said the standard values are groupedinto at least one of the categories user types and or speech trainingpurpose.
 25. A device for speech training, comprising: (A) means forregistering a spoken speech sequence; (B) means for measuring soundingfundamental notes of the speech sequence to be analysed; (C) means foridentifying frequency intervals between at least two of thesefundamental notes in succession; (D) means for assessing the frequencyat which at least one of the frequency intervals thus identified occursin the speech sequence to be analysed; and (E) means for comparing theassessed frequency interval frequency with a preferred frequencydetermined in advance for the user concerned.
 26. A device as claimed inclaim 25, said the device further comprising means for presenting theresults of the comparison between the assessed frequency intervalfrequency and the preferred frequency determined in advance for the userconcerned.
 27. A device as claimed in claim 25 or 26, said the devicefurther comprising means for identifying suitable measures for reductionof the difference between the assessed frequency interval frequency andthe preferred frequency determined in advance.
 28. A device as claimedin claim 25, said the device further comprising a database having atleast one set of standard values to be used as the preferred frequencydetermined in advance for the user concerned.
 29. A device as claimed inclaim 28, said the device further comprising a plurality of sets ofstandard values grouped with regard to at least one of the categoriesuser types and speech training purpose.
 30. A method for diagnosingpathological conditions on the basis of a speech analysis, comprising:(A) uttering a speech sequence by a patient; (B) measuring soundingfundamental notes of the speech sequence to be analysed; (C) identifyingfrequency intervals between at least two of these fundamental notes insuccession; (D) assessing the frequency at which at least one of thefrequency intervals thus identified appears in the speech sequence tothe analysed; and (E) evaluating at least one such assessed frequencyinterval frequency by comparing it with a frequency determined inadvance for diagnostic purposes.
 31. A method as claimed in claim 30,wherein the frequency determined in advance is based on at least onecorresponding previous analysis of a speech sequence from the samepatient.
 32. A method as claimed in claim 31, wherein the frequencydetermined in advance is based on appraisal of corresponding analyses ofat least two speech sequences from the same patient.
 33. A method asclaimed in claim 31, wherein the frequency determined in advance isbased on appraisal of corresponding analyses of more than two speechsequences from the same patient.
 34. A method as claimed in claim 30,wherein the frequency determined in advance is based on normal values.35. A method as claimed in claim 34, wherein patients are furthergrouped in categories, the frequency determined in advance being basedon the normal values applying to the category of users concerned.
 36. Amethod as claimed in claim 34, said the method further comprisingpresenting the results of the evaluation of the comparison between thefrequency interval frequency and the frequency determined in advance.37. A device for diagnosing pathological conditions on the basis of aspeech analysis, comprising: (A) means for registration of an utteredspeech sequence; (B) measurement means for measuring soundingfundamental notes of the speech sequence to be analysed; (C)identification means for identifying frequency intervals between atleast two of these fundamental notes in succession; (D) assessment meansfor assessing the frequency at which at least one of the frequencyintervals thus identified appears in the speech sequence to be analysed;and (E) means for evaluating at least one such assessed frequencyinterval frequency by comparing it with a frequency determined inadvance for diagnostic purposes.
 38. A device as claimed in claim 37,said the device further comprising presentation means for presenting theassessed frequency interval frequency.
 39. A device as claimed in claim37 or 38, said the device further comprising a database having at leastone set of standard values to be used as the preferred frequencydetermined in advance for the user concerned, and preferably a pluralityof sets of standard values grouped with regard to at least one of thecategories user types and diagnosing purpose.
 40. A device as claimed inclaim 37 or 38, said the device further comprising a plurality of setsof standard values grouped with regard to at least one of the categoriesuser types and diagnosing purpose.
 41. A method for speech analysis, themethod comprising: identifying a plurality of notes of a speech sequenceof an individual; identifying frequency intervals between at least twoof the plurality of notes; determining a frequency at which at least oneof the identified frequency intervals occurs in the speech sequence;comparing the frequency of the at least one identified intervalfrequency with a second frequency; and determining a characteristic ofthe individual based at least on the comparison.
 42. The method of claim41, additionally comprising filtering the speech sequence.
 43. Themethod of claim 42, wherein the filtering comprises separating one ormore notes of the speech sequence having a duration shorter than aparticular duration threshold value.
 44. The method of claim 42, whereinthe filtering comprises retaining one or more notes of the speechsequence having a loudness above an amplitude threshold value.
 45. Themethod of claim 41, additionally comprising establishing a pitch meanvalue of a select portion of the speech sequence and using the meanvalue to identify the plurality of notes of the speech sequence.
 46. Themethod of claim 41, wherein the at least two of the plurality of notescomprise two successive fundamental notes.
 47. The method of claim 46,further comprising identifying a frequency change between the twosuccessive fundamental notes.
 48. The method of claim 41, wherein thesecond frequency is calculated from one or more second speech sequencesof the individual.
 49. The method of claim 41, wherein the secondfrequency is calculated from one or more second speech sequences of oneor more other individuals.
 50. The method of claim 41, wherein thesecond frequency is calculated from the speech sequence of theindividual.
 51. The method of claim 41, wherein the second frequencyfurther comprises a preferred frequency, and wherein the methodadditionally comprises presenting the comparison to the individual forspeech training of the individual.
 52. The method of claim 41, whereinthe identifying frequency intervals comprises identifying frequencyintervals between at least three fundamental notes in succession.
 53. Asystem, comprising: a processor configured to identify a plurality ofnotes of a speech sequence of an individual, identify a plurality offrequency intervals, each frequency interval occurring between a pair ofthe plurality of notes in the speech sequence, and calculate a frequencyof the plurality of frequency intervals in the speech sequence; and amemory configured to store a second frequency, wherein the processor isfurther configured to compare the calculated frequency with the secondfrequency and to output one or more results based at least on thecomparison.
 54. The system of claim 53, further comprising a filterconfigured to separate notes from the speech sequence that do not exceedat least one of a threshold duration and a threshold amplitude.
 55. Thesystem of claim 53, wherein the calculated frequency comprises aproportion of the plurality of frequency intervals to a total number ofintervals in the speech sequence.
 56. The system of claim 53, whereinthe processor is further configured to determine a characteristic of theindividual based at least on the comparison.
 57. The system of claim 53,wherein the processor is further configured to detect a position of atleast one of the plurality of frequency intervals with respect to asecond frequency interval.